Proteins are made of amino acids. The information that leads to the creation of amino acids in living organisms is contained in their DNA.
The formation of an amino acid involves the transcription of DNA into a RNA molecule. This is then translated on the ribosome into amino acids. The information for a single amino acid is contained in a codon which is a set of 3 nucleotides. There are four types of nucleotides possible that vary based on their structure: adenine, guanine, cytosine and thymine. 4 types of nucleotides in sets of 3 allow a total of 64 different codons. All the complex proteins in our body are encoded in our DNA with this relatively small number of codons.
As the small protein is composed of 60 amino acids, the DNA gene for this protein is made up of 180 nucleotides.